Publish a tool without an HTTP route

Register a Nest provider as an MCP tool without creating a controller endpoint. The tool appears in the same search and detail catalog as your HTTP operations and runs through its own access policy and runtime validators.

Define the provider tool

The demo API's note-summary.ts contains this complete example:

import { Injectable } from "@nestjs/common";
import { defineProviderTool } from "@sezzlee/sdk-nestjs";
import { z } from "zod";

@Injectable()
export class NoteSummaryService {
  summarize(text: string) {
    return { characters: text.length, words: text.trim().split(/\s+/u).length };
  }
}

export const noteSummaryTool = defineProviderTool({
  name: "summarize_note",
  description: "Count the characters and words in a note.",
  provider: NoteSummaryService,
  input: z.strictObject({ text: z.string().trim().min(1).max(10000) }),
  output: z.strictObject({ characters: z.number().int(), words: z.number().int() }),
  annotations: { readOnlyHint: true },
  tags: ["notes"],
  access: "public",
  execute: (service, input) => service.summarize(input.text),
});

The explicit public policy permits any caller admitted by your MCP transport. It does not remove transport authentication. For a private tool, supply an access callback that checks context.caller against your application's current permissions. It runs again on invocation and when reading a stored result, so a discovery result cannot preserve revoked access.

Register it with the application

Add NoteSummaryService to your application's providers, and push noteSummaryTool into options.tools in SezzleeModule.forRoot. Both changes are present in the demo API's app.module.ts. No controller or HTTP route decorator is needed. Keep the provider and its dependencies independent of HTTP request scope.

Use search_tools to find summarize_note, then load_tool and invoke_tool. Arguments { "text": "hello world" } return { "body": { "characters": 11, "words": 2 } }. A direct HTTP request to /summarize_note returns 404 in the demo. The agent-client --scenario provider scenario checks both the MCP result and that HTTP response.